Development of new methods of analysis of electronic spectra will be continued. Spectra of pyridoxal phosphate-dependent enzymes, flavoproteins, purines, pyrimidines and various proteins will be examined. Attempts will be made to construct spectrastructure correlations and to establish whether chemical information can be obtained from spectral band widths. The spectra of Schiff bases and bound coenzyme bands will receive special attention. Synthesis of several new analogs of pyridoxal phosphate will be carried out. Among these are a 5'-sulfonate (-Ch2-CH2-SO32-), a nitro compound, the 5'-phosphoramidate and a pyrophosphate. A benzenoid analog will also be made as will various derivatives of pyridoxamine phosphate with complex side chains. Attempts will be made to quantitatively understand electronic interactions within Schiff bases of pyridoxal phosphate and in other heterocyclic rings. Reactions of pyridoxal phosphate analogs with aspartate aminotransferase, glutamate decarboxylase and other enzymes will be investigated. The nature of covalent interactions of pyridoxal-5'-sulfate, of a 5'-vinylcarboxylate analog analog and of a 4-ethynyl analog with aspartate aminotransferase will be studied. Attempts will be made to understand the chemistry of the 340 nm chromophore of the beta subform. The pH-dependent spectral transition in glutamate decarboxylase will be studied and various other experiments with these and other pyridoxal phosphate-dependent enzymes will be conducted.